In most omnibuses, coaches railway wagons and other means of collective transport, passengers can for their greater comfort incline the backrests of their seats at will; it is also possible in some cases to move the seat laterally towards the gangway, in order to move it further away from the adjacent seat and thus make more room available.
Once the passengers have left the vehicle it is advisable to return each of the seats to its initial position, an operation which is mostly performed manually by the driver of the coach or the ticket inspector, with the attendant loss of time.
Systems have been developed to allow the driver to carry out this operation for all the seats at once, but such systems involve a system of electrical control for each seat and a connection to the driver's position, and therefore represent a very high cost in materials, equipment and labor for fitting.